During the next year, we will compare the expression of histocompatibility antigens on melanoma cells to those on autologous fibroblasts transformed with SV40. We will also investigate the roles of histocompatibility antigens and receptors for breakdown products of the third complement component in cells' susceptibility to viral infection. The expression of melanoma associated antigens will be quantitated on cultured melanoma cells as they move through the growth cycle. The susceptibility of these cells to complement dependent lysis should increase after treatment with the sulfhydryl compound 2-aminoethylissothiouronium bromide, which we will attempt to show. Simultaneously, the humoral immune defense in melanoma patients undergoing immunotherapy will be monitored and correlated with the clinical course of the disease. Finally, we will exchange our allo and xenoantisera to melanoma associated antigens with other laboratories is an effort to standardize reagents used to characterize melanoma associated antigens. BIBLIOGRAPHIC REFERENCES: Reisfol, R.A., Pellegrino, M.A. and Ferrone, S., The immunologic and molecular profiles of HLA antigens isolated from urine., J. Immunol. 118:264, 1977. Ferrone, S., Pellegrino, M.A. and Cooper, N.R., Expression of C4 on human lymphoid cells and possible involvement in immune recognition phenomena. Science 193: 53, 1976.